Development of an electrochemical insulin sensor based on the insulin-linked polymorphic region

Jennifer Y. Gerasimov, Cody S. Schaefer, Weiwei Yang, Rebecca L. Grout, Rebecca Y. Lai

Research output: Contribution to journalArticlepeer-review

59 Scopus citations


Here we report the design and fabrication of an electrochemical aptamer-based (E-AB) sensor for detection of insulin. The aptamer used in this study is the insulin-linked polymorphic region (ILPR) sequence, a G-rich sequence that presumably undergoes ligand-induced folding to form a G-quadruplex in presence of insulin. Our circular dichroism data, however, suggests that the ILPR sequence, even in absence of the target, is predominantly in a G-quadruplex-like form. Insulin binding, however, has shown to further induce the formation of the G-quadruplex. To evaluate the potential of the ILPR sequence as a biosensing element, we constructed two E-AB insulin sensors that are identical in all aspects but the location of the methylene blue (MB) redox label. We find that the sensor fabricated with internal MB-modified probes (In-IT) shows enhanced sensing behavior when compared to one fabricated using terminal-MB modified probes (In1). The improvements observed with the In-IT sensor could be attributed to the more effective obstruction of electron transfer upon insulin binding. Overall, both sensors perform well, affording a detection limit of 10 nM and 50 nM for the In-IT and In1 sensors, respectively.

Original languageEnglish (US)
Pages (from-to)62-68
Number of pages7
JournalBiosensors and Bioelectronics
Issue number1
StatePublished - Apr 5 2013


  • Circular dichroism
  • Electrochemical
  • Insulin
  • Insulin-linked polymorphic region
  • Methylene blue

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry


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